Re: 1978 Dodge Champ20

Dodge didn't make class A motorhomes. Could it be your talking about a Winnebago on a Dodge chassis? Back in that era the Dodge chassis had 413, 413P 440 & 440P engines. The P engines were truck engines with a high mount water pump. The standard B block water pump had a 4 bolt mount ver. a 5 bolt mount for the P engine. Some of those old beasts had od sized tiers that were hard to find. 16.5" I think.........
Anticipate about 4 MPG..........

Richard